Direct Access Storage Devices (DASD), such as disc drives, are well-known in the art. A typical prior art disc storage apparatus has a base with one or more data storage discs rotatably mounted on the base and a motor to rotate the discs. A pivot assembly is mounted on the base and is fixedly attached to the base at one end of the pivot assembly. A transducer assembly having one or more transducer heads is mounted on the pivot assembly at the other end. An actuating means, such as a voice coil motor, is positioned between the transducer assembly and the fixed end of the pivot assembly. The voice coil motor moves the pivot assembly, thereby moving the transducer assembly with the transducer heads moved over the surface of the discs. See, for example, U.S. Pat. Nos. 4,751,597 and 4,300,176. Although such an arrangement is compact, these prior art devices have suffered from the disadvantage of poor frequency response.
Further, as glass becomes the choice of consideration for the substrate of the storage discs, in the disc drive, it becomes desirable to retain or hold the glass discs in place, such that the glass will not slip, warp or break. In addition, it is desired to be able to control the amount of the clamping force on the stack of discs. The force cannot be so high as it will break the glass disc, nor it can be so low as to cause the disc to slip under shock and vibration. The clamping force must be constant or nearly so with dimensional changes experienced under temperature variations.
Conventional retaining rings, used in automobiles and agricultural equipment, purchasable from, for example, Walds Truarch, is well-known in the art.
Finally, as the size of discs decreases, it becomes increasingly desirable to use zone band recording, to record magnetic information on the discs. In zone band recording, different density of recording is achieved at different radius, resulting in a constant number of bytes per track recording. However, zone band recording requires the transducer head to be at a nearly constant height over the disc surface. In the prior art, one company, DASTech, has proposed the use of radically-designed transducer heads to maintain the head at a constant or substantially constant flying height over the disc. However, to date, it is not believed that a conventional head can be maintained at a constant flying height over the surface of the disc.